Formation of Nanoporous Anodized Tin Oxide Films in Electrolyte Containing F⁻ and S²⁻

Abstract

Nanoporous anodized tin oxide films have many potential applications in the fields of photocatalysis, sensors and electrode materials. In this paper, we found that potential played a dominant role in the morphological evolution of anodized tin oxide films in electrolyte containing F− and S2−. The critical potential for the formation of nanoporous structure was determined. Porous anodized tin oxide films with different nanostructure can be prepared by the application of low anodization potential and high anodization potential. The I–V curve analysis showed that the change of the nanoporous of tin oxide films at different potentials could be attributed to the oxygen which generated by the electronic current. The valence regulation of Sn element in anodized tin oxide film can be achieved by controlling the potential.

A review: research progress on the formation mechanism of porous anodic oxides

“…23,28,54,69,88,[109][110][111][112][113] These metals can be prepared by anodization to form films with regular nanotube arrays which have shown wide application potential in a wide variety fields such as sensors, supercapacitors, and photocatalysis. 111,[114][115][116][117][118][119][120][121][122][123][124][125][126] Because of its simple and efficient preparation process and low cost, it also has a good prospect in future industrial production. Therefore, further research on the mechanism is of great significance to the preparation of nanoporous materials with precise structures.…”

Debunking the essential effect of temperature and voltage on the current curve and the nanotube morphology

“…2 is a diagram of the 'oxygen bubble model' growth. According to the 'oxygen bubble model' [32][33][34][35][36][37][38] and ionic current and electronic current theories. [39][40][41][42][43][44][45] Two reactions happened at the anode.…”

“…According to the 'oxygen bubble model' [32][33][34][35][36][37][38] and the ionic current and electronic current theories, [39][40][41][42][43][44][45] when the temperature is high, the magnitude of electronic current and ionic current is large, so the mold effect is obvious, regular nanotubes can be formed, as shown in Fig. 1a.…”

“…That is because the eld-assisted dissolution reaction itself has nothing to do with the current. A new explanation for the decreasing current under low temperature is given based on the 'oxygen bubble model' [32][33][34][35][36][37][38] and the ionic current and electronic current theories. [39][40][41][42][43][44][45] We propose that the electronic current, rather than the eld-assisted dissolution, plays an important role in the growth of nanotubes.…”

Effect of Dense Oxide Film Thickness on the Growth of Lower Layer Nanotubes

“…Electrochemical synthesis and electrochemical anodization have been extensively studied in the last decade. [1][2][3][4][5][6][7][8][9][10][11] In general, if titanium is used as the anode and graphite as the cathode, the surface of the titanium will grow into a dense oxide film. However, it was found experimentally that if an electrolyte containing fluoride ion was used for anodizing, TiO 2 nanotubes would grow instead of a dense oxide film.…”